What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

A biopsy of involved tissue should confirm clinical suspicion of LRCHL.(Table 1)

Table 1.

Test Results Indicative of the Disorder

Tissue Biopsy

Immunohistochemistry on Tissue Biopsy

Presence of Reed-Sternberg cells and mononuclear variants in a background of small, non-neoplastic lymphocytes.

Reed-Sternberg cells are CD30+, CD45-, usually CD15+, and PAX5+, but are usually negative for other B-cell markers. The background small lymphocytes are mostly B-cells in the majority of cases.

After diagnosis, the disease should be staged (see chapter on Classical Hodgkin lymphoma).

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?

As with all types of CHL, a fine needle aspiration, limited tissue biopsy, such as a core biopsy, or biopsy of a small, partially involved node may yield false-negative results in LRCHL.

What Lab Results Are Absolutely Confirmatory?

A biopsy of involved tissue confirms a diagnosis of LRCHL.

The Reed-Sternberg cells of LRCHL resemble those of other CHL subtypes but may be less frequent in the involved tissue. Unlike other subtypes of CHL, the inflammatory background of LRCHL consists almost exclusively of lymphocytes, with rare or no eosinophils or neutrophils. Fibrous collagenous bands are absent. B-cell follicles and reactive germinal centers are present in most cases; the Reed-Sternberg cells in such cases are located mainly at the periphery of the B-cell follicles. Some cases may have a diffuse appearance with a predominantly T-cell background.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

Immunohistochemistry plays a critical role in confirming a diagnosis of LCRHL, as this disease may mimic nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) morphologically. Unlike the Reed-Sternberg cells of NLPHL, the Reed-Sternberg cells of LRCHL express CD30, usually express CD15, are negative or only focally positive for CD20, and lack expression of CD45 and CD79a.

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?

In small biopsies and with an incomplete immunohistochemistry panel, LRCHL may be confused with nodular lymphocyte predominant Hodgkin lymphoma. The nodular architecture and small B-cell-rich nature of many LRCHL cases may also lead to misdiagnosis as follicular lymphoma or even as reactive follicular hyperplasia if the neoplastic Reed-Sternberg cells are overlooked.